221/Repairs: Difference between revisions

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m (Failed C714)
 
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(Common Problems)
=Common Problems=


==Failing PSU==
The 221 has a switching power supply. It has
The 221 has a switching power supply. It has
a transformer coupled trigger circuit which produces
a transformer coupled trigger circuit which produces
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is the thing to fail.<br>
is the thing to fail.<br>


==Failed capacitors==
[https://www.youtube.com/@justanotherelectronicsblog5490/videos justanotherelectronicsblog@YouTube] found C714 short when [https://www.youtube.com/watch?v=bZ6agALKXjs fixing his 221]


[[Category:Instrument repair reports]]
[[Category:Instrument repair reports]]

Latest revision as of 10:28, 19 October 2023

Common Problems

Failing PSU

The 221 has a switching power supply. It has a transformer coupled trigger circuit which produces a DC level base trigger. It gets fried when the battery gets old and draws too much current.

More often than not, the T633 Transformer (part number 120-0876-00) is the thing to fail.


Failed capacitors

justanotherelectronicsblog@YouTube found C714 short when fixing his 221